Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Ill VALUES The term " values " may be defined as the ' intensity of light reflected from objects, though this definition is not precisely correct from the pictorialist's point of view, since some colors have a psychic effect different from their actual photometric value. Thus, we are accustomed to associate yellow with light and warmth, so a yellow object may appear lighter to the eye—or, rather, to the mind—than, say, a violet object which has the same reflecting power. Nevertheless, the definition as given may be accepted as generally satisfactory. It must be understood that the light values of a given object are by no means constant, for they vary with the quality and intensity of the incident illumination, and even under a given light they are not necessarily always the same, so far as the pictorial effect is concerned. For example, suppose one is standing, about sunset, facing the west, and there is a row of trees in the middle distance. The eyes will naturallyaccommodate themselves to the illumination of the sky, and as a result of the contraction of the pupils no detail will be seen in the dark mass of the trees, which will appear opaque and empty of gradation, and of an intense blackness. If, however, the eyes be shaded from the light of the sky, details and gradations will leap out in a most astonishing manner in the trees and foreground. Suppose, now, that after looking at the trees with the eyes shaded for a time, the gaze is again directed at the sky, and it will be found that this, which before may have had considerable gradation, now appears white and blank, if, indeed, it is possible to look at it for more than a second or so. From this it is evident that the values in any arrangement must be considered in relation to one another, and as a whole—that it is ...